1. Field of the Invention
The present invention relates to a tilt device for a vehicular steering column, in particular, which is adapted to adjust the angle of the steering column through engagement/disengagement between a fixed gear and a movable gear pivoting under the regulation due to reciprocation of a lock slider penetrated by a tilt lever.
2. Description of the Related Art
In general, a tilt device is so designed to tiltingly adjust the angle of a steering wheel in a vertical direction according to physical condition or driving posture of a driver.
A conventional tilt device 100 will be schematically described with its structure according to the operation in reference to FIG. 1. When an operating lever 120 with one hinged end is pivoted in order to adjust the angle of a fixed steering column 110, a rod 122 cooperates so that a tilt bracket 130 also is pivoted counterclockwise under the regulation of a wedge 136 which supports the rear face of a movable gear 140 with a protrusion 134 so formed to couple with a hole 132 of the tilt bracket 130. The movable gear 140 is released from engagement with the fixed gear 150 as a projection pin 142 settled in an inclination groove 131 of the tilt bracket 130 slides down along an inclined plane.
Then, the angle of the steering column 110 is adjusted, and upon releasing external pressure applied to the operating lever 120 penetrating a lock slider 124, the fixed gear 150 and the movable gear 140 are engaged again as the tilt bracket 130 returns to its original position. Reengagement of the gears 140 and 150 is tightly fixed by the wedge 136.
Further, the fixed gear 150 and the movable gear 140 are installed in a pair in order to increase the engagement strength of the fixed and movable gears 150 and 140. The movable gear 140 ensures a position on the same axis by a gear bush (not shown) having a projection pin (not shown) and a fixing bolt 160.
In the conventional tilt device 100 configured as above, however, the structure to make the driving force of the operating lever 120 cooperate with pivoting of the movable gear 140 engaged/disengaged into/from the fixed gear 150 is complicated. Further, a projection pin of a gear bush is occasionally fractured. This directly results in high cost of manufacture of the tilt device 100.
The operating direction of the wedge 136 is identical with the rotating direction of the tilt bracket 130. This may cause an insufficient gap between the operating member 140 and the wedge 136 so as to generate an operational error. Further, the operating direction of the operating lever 120 is different from that of the tilt bracket 130 so that loss takes place until the operating force of the operating lever 120 reaches the tilt bracket 130. Then, a certain amount of force is applied that is larger than the actually required operating force of the operating lever 120 which reduces the operating ability.
As another problem, the operating lever 120 and the lock slider 124 regulating the operating lever are coupled through simple penetration only, thereby causing the fixed state of the operating lever 120 to be unstable, as well as generating noises due to mutual friction.